The applications of a work machine, such a hydraulic shovel, include sieving where the stick-in/out operations and the bucket-in/out operations are repeated in order to remove dirt and gravel from the scooped load using a skeleton bucket or to scatter the load on the ground.
In the past, an operator has manually operated an operation lever in order to execute this type of sieving. In recent years, however, there has been known a work machine that automates the sieving in which a work device is vibrated automatically by causing a controller to simulate the signals input from the operation lever.
According to the known configuration, not only is it possible to independently set the positive and negative vibration amplitudes of a work device, but also the center between the positive vibration amplitude and the negative vibration amplitude is made variable by a manual operation.
According to another known configuration, the vibrations and the number of vibration amplitudes of a work device can be changed by using the operator's operation of an operation lever as a trigger.